A group of seven laboratories in clinical and basic neuroscience are requesting funds to obtain a Philips CM 12 Scanning/ Transmission Electron Microscope. Thirty five scientists and support staff associated with these labs are involved in electron microscopy. The Philips CM 12 will in part serve as a replacement for a 15 year old Philips EM 201. Many of the critical features of the newer microscope are not available for the older one; these features include a goniometer stage, scanning electron microscopy for both backscattered and secondary electrons, video output, computer-assisted video intensification and storage, and online quantitation. Principal investigators in the seven labs all are funded by NIH to study neuroscience questions of which all or part are based on ultrastructural analysis. This equipment will allow us to achieve better quality electron microscopy. It will also facilitate new scientific directions based on the specialized features of the Philips CM 12, and because of the more reliable operation and video storage will aid in the accommodation of the growing number of personnel here involved in ultrastructural work.